Precise timing
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Hi
Anyone know of a way of timing procs, functions or a piece of code that runs in under 1 millisecond??
Is it possible?
More out of interest than serious requirement,
Thanks
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If a piece of code actually runs in under a millisecond, why would you care to time it?
I think SQL Server only support timings to within 3 milliseconds.
Gregory Larsen, DBA
If you looking for SQL Server Examples check out my website at http://www.geocities.com/sqlserverexamples
Gregory A. Larsen, MVP
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Well like I said, was more out of interest that a real need.
But if you had a piece of code that could be written in two different ways, and both those ways ran in under a millisecond, it might be interesting to see which actually ran faster (given that SQL can do a lot of things in a millisecond), especially if it was to be used multiple times.
With reference to your second comment, comparing getdate() (using datediff(ms,...) ) both before and after a piece of code would seem to suggest that you can get timings down to 1 millisecond, is this not the case?
Thanks
David
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If you cannot get the small time increments that you are looking for by simply using datepart(ms, @timer, getdate()) then why not loop around your code say 100 times.
This will magnify the time taken for the code to process. Once you run your alternative code within a loop 100 times you will have the comparison you are looking for.
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To verify the time to 3 milliseconds try the following code:
declare @datetime datetime
set @datetime = '2002-12-16 23:59:59:993'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-16 23:59:59:994'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-16 23:59:59:995'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-16 23:59:59:996'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-16 23:59:59:997'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-16 23:59:59:998'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-16 23:59:59:999'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00.000'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:001'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:002'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:003'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:004'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:005'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:007'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:009'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:009'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:010'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:011'
print convert(char(17),@datetime,114)
set @datetime = '2002-12-17 00:00:00:012'
print convert(char(17),@datetime,114)
As far as timing to determine which code is faster. Try running each set of code a million time, and compare how long it takes.
This should be measurable.
Gregory Larsen, DBA
If you looking for SQL Server Examples check out my website at http://www.geocities.com/sqlserverexamples
Gregory A. Larsen, MVP
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Consider it verified!
In which case, can I revise my original post to "Can you time something that runs in less that three millisecond"...no never mind!!, Thanks for your replies
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